TextHelper::convertHtmlToBbCode

static function convertHtmlToBbCode($html)
{
	$html = strval($html);
	if($html === '')
	{
		return '';
	}

	$allow = [
		'ANCHOR' => 'Y',
		'BIU' => 'Y',
		'IMG' => 'Y',
		'QUOTE' => 'Y',
		'CODE' => 'N',
		'FONT' => 'Y',
		'LIST' => 'Y',
		'SMILES' => 'Y',
		'NL2BR' => 'Y',
		'VIDEO' => 'Y',
		'TABLE' => 'Y',
		'ALIGN' => 'Y',
		'P' => 'Y',
		'CUT_ANCHOR' => 'Y',
	];

	$result = (new \CTextParser())->convertHTMLToBB($html, $allow);

	// \CTextParser leaves some html tags, escaping them instead of removing/transforming them
	// remove those remaining tags, and escape the result for backwards compatibility
	return htmlspecialcharsbx(strip_tags(htmlspecialcharsback($result)));
}